EXAMINE THIS REPORT ON POS88

to check the effects of many constraints on mutational tolerance through range, we chose E. coli dihydrofolate reductase (DHFR) like a design system. DHFR is an essential enzyme in folate metabolism that reduces dihydrofolate to tetrahydrofolate and it is essential for thymidine creation. Using this action as The premise for an in vivo range assay�